Kraft has refused to extend a two-year pledge made in the wake of last year's controversial takeover of Cadbury not to lose any UK manufacturing jobs.

The sale of one of Britain's best-loved companies to a foreign predator continues to rankle and MPs had hoped to win a longer reprieve for its 3,000 factory workers at business select committee hearing.

The committee chairman, Labour MP Adrian Bailey, said it was a "disappointing" outcome and one that was magnified by the absence of Irene Rosenfeld, Kraft's chief executive. The US food group was accused of sending "junior executives" in the shape of the heads of its UK and European operations, Nick Bunker and Trevor Bond.

Chicago-based Rosenfeld turned down three requests from the committee to appear, Bailey said, including the offer to answer questions via video link.

An exchange of letters between Kraft and Bailey shed some light on her rationale. In a letter written by its corporate and legal affairs director, Marc Firestone, who was also appearing before the committee for a second time, Kraft said that there appeared to be a desire to have a "star witness towards whom ill-founded allegations and insults can be made. A review of last year's hearing shows that it went far beyond spirited debate to a remarkable level of rancor."

Kraft declined to comment on Rosenfeld's whereabouts.

Rosenfeld earned notoriety for her conduct during the hostile takeover after reneging on a promise made at the outset of the bid to keep open the Cadbury plant at Somerdale near Bristol, which raised false hopes for the 400 employees who were braced for its closure. She is thought to have visited Bournville just once since the takeover last January.

Rosenfeld's about-face earned the US listed maker of Philadelphia cheese and Oreo biscuits a public reprimand from the UK Takeover Panel and the company has been struggling to rehabilitate itself in the eyes of the British public. That cause was dealt a further setback last year when it emerged that Kraft was shifting parts of the 186-year-old British business to Switzerland in a move likely to deprive the UK exchequer of millions of pounds of tax. Firestone, however, told the MPs that the effect on its tax bill would be "de minimus".

The two-year jobs pledge was made at a hearing last March and Bond would not rule out compulsory redundancies at Kraft's six UK factories beyond March 2012. He added that "improving productivity was the best chance" for the UK manufacturing base to be viable in the long-term. To that end, he said that some contracts, including deals to make chocolate drinks and Easter eggs, had been pulled back from third party suppliers. "We are increasing our investment in Bournville and bringing jobs back into the network but we live and work in uncertain times."

Jennie Formby, the national officer for food and drink at the union Unite, said that Kraft workers were in the middle of a "two-year honeymoon period". She added: "We have grave concerns that factories may close or that we will see restructuring that will lead to a loss of jobs." The enlarged group employs 5,500 people and a question mark is currently hanging over 600 staff who work in office based roles, such as administration and are not covered by the no compulsory redundancies guarantee. The number of support offices is being reduced from five to two, with Kraft's UK head office in Cheltenham among the ones earmarked for closure. The company said consultation process was under way but could not say how many jobs would go as a result of the rationalisation.

Bailey said it "would not hesitate" to recall Kraft executives to further hearings if it felt it was not abiding by the undertakings given the committee, which also include continuing Cadbury's traditions of philanthrophy and ethical sourcing.